Generally a conventional type of micro vacuum device has an electron emitter, a gate, and a collector each formed in a vacuum on a silicon substrate by making use of the semiconductor micromachining technology with the gate provided adjacent to the electron emitter having a needle-like or a thin film form.
However, in the conventional type of micro vacuum device, as a degree of vacuum becomes lower, the field emission of electron characteristics is degraded due to such causes as absorption of gas into a surface of an electron emitter.